1. Field of the Invention
The present invention relates to a lifting apparatus, and more particularly to a lifting apparatus of adjusting spaced-apart tines to fit a load depending on the fork pocket spacing, height, and width of the load.
2. Brief Description of the Prior Art
Fork tines have been used for lifting and moving a load. Typically, fork tines mounted on a frame of a lifting apparatus are spaced-apart from each other. Because a height of the frame and a distance between fork tines are fixed, the lifting apparatus is limited to use for lifting and carrying a fixed-sized load. A plurality of lifting apparatuses and a bulky and complicated lifting apparatus have been used for the various sized loads. Moreover, depending on various sizes of a width, a height, and a length of the loads, the lifting apparatus having only one dimensional adjustment is not enough to lift and move the various sized loads.
In efforts of adjusting a distance between fork tines or a height of the frame in the lifting apparatus, U.S. Pat. No. 5,984,050 for a Carriage Suspension For Lift Truck issued to Ronald, U.S. Pat. No. 5,829,948 for a Multipurpose Lift Apparatus and Method issued to Becklund, U.S. Pat. No. 5,758,747 for a Mast Support for Forklift issued to Okazaki et al., U.S. Pat. No. 5,722,511 for a Lifting Vehicle and Method of Operating the Vehicle issued to Wakamiya, U.S. Pat. No. 5,586,619 for a lifting Apparatus issued to Young, U.S. Pat. No. 5,509,774 for a Load Clamping apparatus with an Increased Extent of Vertical Movement issued to Yoo, U.S. Pat. No. 5,379,863 for a Crane issued to Sugawara et al., U.S. Pat. No. 5,409,346 for a Self-Loading and Unloading Forklift Truck issued to Grether, U.S. Pat. No. 4,358,239 for a Warehouse Crane Including Inclinable Tote Pan Puller issued to Dechantsreiter, and U.S. Pat. No. 3,993,202 for a Storage System With Adjustable Interconnected Crane Towers issued to Neitzel disclose various types of lifting apparatuses having the fork tines. These references, however, show mechanisms adjusting only one dimension of the fork tines depending on the size of the load or complicated mechanisms adjusting one or two dimensions of the fork tines and including a tractor or a truck.
Regarding screw jack mechanisms, U.S. Pat. No. 5,118,082 for a Electrical Operated Screw-Type Jack issued to Byun, U.S. Pat. No. 4,641,813 for a Dual Automobile Jack For Consumer Use issued to Arzouman, and U.S. Pat. No. 4,609,179 for a Screw Jack issued to Chem et al. disclose typical structures of screw jacks. These references, however, do not show any application for a lifting apparatus.
Therefore, we have noticed that the conventional method and apparatus fail to show a lifting apparatus having a variable range of the width, height, and length of the frame and the fork tines depending on various sizes of width, height, and fork pocket spacing of the loads and that the lifting apparatus as shown in these references are not enough to lift and move various sized loads in width, height, and length. Moreover, when the various sized loads should be located in a limited space or a designated storage location, the conventional lifting apparatus can not move within the space and carry the various sized loads into the limited space.
It is an object of the present invention to provide a lifting apparatus suitable to lift and carry all various sized loads.
It is another object of the present invention to provide a lifting apparatus able to load a container into a limited space and a designated storage location.
It is yet another object to provide a lifting apparatus able to adjust to any width, height, and fork pocket spacing.
It is still another object to provide a lifting apparatus able to adjust a frame to fit a load.
It is a further object to provide a lifting apparatus able to access a load within a minimum amount of aisle space.
It is also another object to provide a lift apparatus able to adjust all of the width, the height, and fork pocket spacing of the frame or fork tines simultaneously.
These and other objects may be achieved by providing a lifting apparatus including a horizontal framework, two pairs of extension assemblies, a pair of upper, middle, and lower telescoping mast assemblies, and two pair of fork tine assemblies. Each one of the pairs of the extension assemblies, the telescoping mast assemblies, and the fork tine assemblies is identical to the other one in structure and function. The horizontal framework is coupled to an overhead bridge crane and is accessible to any load located within a minimum amount of aisle space.
The horizontal framework includes a pair of horizontal supporters spaced-apart from each other and a pair of horizontal connectors secured to both ends of the horizontal supporters. Two brackets fixed between the spaced-apart horizontal supporters connected to the bridge crane trolley by securing to hooks or twist lock connectors of the bridge crane trolley to brackets.
A horizontal motor mounted on one of the horizontal supporters is connected to a frame shaft through a first shaft extended from the horizontal motor, to a pulley and belt assembly. The frame shaft is coupled to a pair of gear reduction units mounted on the horizontal supporter. The output end of each gear reduction unit is coupled to a pulley and belt assembly. Each pair of pulley and belt assemblies directs torque to a pair of inboard pinion gears and outboard pinion gears, both of which operate in synchronized motion through a final pulley and belt drive.
All of the extension assemblies, the upper, middle, and lower telescoping masts, and fork tine assemblies move toward or from the horizontal framework. Therefore, a distance between pairs of extension assemblies, the upper, middle, and lower telescoping masts, and fork tine assemblies is adjusted by the rotation of the horizontal motor and the frame shaft pulleys, belts and pinion gears.
The upper mast assembly is mounted beneath the extension supporter and includes two upper vertical beams spaced-apart from each other and two upper horizontal side bars attached to the spaced-apart upper vertical beams to maintain a distance between the spaced-apart upper vertical beams. Pairs of rails are formed on the upper vertical beams. A vertical motor mounted on the extension supporter is coupled to vertical screws within the power screw jack through a second shaft extended from the vertical motor. The vertical screws are rotatably mounted on the upper vertical assembly. Ends of the vertical screws are coupled to the second shaft within the power screw jacks while the other ends of the vertical screw are inserted into holes formed on the middle horizontal beam through fixed nuts attached to the middle horizontal beam. A thread portion formed inside of the fixed nut is coupled to a peripheral outside of the vertical screw.
A middle mast assembly coupled to the vertical screw of the upper mast assembly through the fixed nut includes two middle vertical beams spaced-apart from each other and two middle horizontal beams attached to spaced-apart middle vertical beams to maintain a distance between spaced-apart middle vertical beams. Two pairs of rails formed on the two middle vertical beams have a telescoping relationship with each pair of rails of upper vertical beams.
A lower mast assembly includes two lower vertical beams spaced-apart from each other and lower horizontal beams, each end coupled to spaced-apart lower. vertical beams. A lifting chain is coupled to both the upper and lower mast assemblies through a pulley rotatably mounted on the middle horizontal beam of the middle mast assembly. An anchor is secured to the lower horizontal beam. The lifting chain has one end connected to the anchor and the other end connected to the lower horizontal side bar of the upper mast assembly while a portion of the lifting chain is wound around a peripheral surface of the pulley. A fork tine assembly is mounted on the lower mast assembly, and two fork tines are spaced-apart from each other by a pair of tine motors and power screw drive-shafts mounted on the lower mast assembly.